This invention pertains to automatically operable lock structure for a window having a pivotally-mounted window sash with improvements in such mechanism providing for drawing the sash tightly closed against the frame with both closing and lifting forces applied to the sash and with window-operated structure for positively releasing the locking structure.
The known prior art includes the following patents:
Lang 2,036,151 Lang 2,094,990 Reynaud 2,157,016 Reynaud 2,952,882 Reynaud 3,085,299
In the above-listed patents, many different structures are disclosed for drawing a window tightly closed. Some of these mechanisms require a separate manual operator as part of an auxiliary locking structure. Those disclosures which provide for automatic operation of a locking structure in response to closing of the window do not exert the desired forces with the desired mechanical advantage.